During the past nine years, the DERC, with its Core Laboratories, Enrichment Program and support for Pilot and Feasibility. studies, has played a major role in allowing for expansion in the scope and intensity of research at the Joslin Diabetes Center and Harvard Medical School. The DERC has provided essential support for interdisciplinary studies and junior faculty, and a critical infrastructure for both basic and clinical research. It is not surprising, therefore, that over his period there has been a further strengthening of the research effort at the Joslin, a significant increase in the publications in peer-reviewed journals and a more than 50% increase in training of research fellows. Recognizing this growth in research activity and the importance of the research mission, the Joslin added three floors to its building with over 30,000 sq. ft. of additional research space, and has renovated research space in the original building, all of which has resulted in improved laboratory space for individual investigators and the DERC Core Laboratories. In this renewal application, we have attempted to build on those strengths by eliminating Core Laboratories which were underutilized (such as Flow Cytometry) and adding new Cores (such as the Computer Resource Core). In addition, we have expanded the scope of the services provided by most Cores, but especially, the Peptide Biochemistry Core, the Microscopy Core, the Radioligand Assay Laboratory for the Clinical Research Core and the Transgenic Animal Core. At the last renewal we added one Pilot and Feasibility grant to our Center for use by scientists in the Longwood area outside the Joslin and affiliated with Harvard hospitals (e.g. Harvard Medical School, Children's Hospital, Beth Israel Hospital, Brigham and Women's Hospital, Deaconess Hospital, Dana Farber Cancer Institute, Center for Blood Research and Massachusetts General Hospital), and this program will continue. Within the DERC and the Joslin we have been particularly encouraged over the past four years by the development of younger faculty who have bean supported directly and indirectly by the DERC, such as Drs. Jackson, White, Hattori, Maratos-Flier, Rhodes, Shoelson, Lipes, Goodyear and others. These individuals, along with more established investigators and new faculty recruited by virtue of expansion, create the scientific base and strength of the Joslin DERC. Finally, the strong intellectual stimulus provided by the activities of the Enrichment Program have a major impact, not only at the Joslin, but in the whole Harvard-Longwood Medical area.